1. Field of the Invention
The present invention relates generally to an electrical connector, and more particularly to an electrical connector for connecting a Central Processing Unit (CPU) with a Printed Circuit Board (PCB) during a test procedure for the CPU.
2. Description of Related Arts
An electrical connector used for connecting the CPU with the PCB, especially in a test procedure for the CPU, mainly comprises an insulative housing, a plurality of contacts received in the insulative housing for electrically connecting electrical pads of the CPU with circuit pads of the PCB and a cover for activating the CPU to connect with the contacts. The contacts are usually curved to have flexible deflection. Accordingly, the insulative housing has larger passageways to receive the contacts.
Referring to FIG. 1 of a cross-section view of an electrical connector as a first prior art, the electrical connector is connected with a CPU 12 by a plurality of solder balls 120. The electrical connector comprises an insulative housing (not labeled) and a plurality of contacts 10 received in the insulative housing. The insulative housing forms an immovable layer 14 in an upper level and a moveable layer 16 in a lower level, keeping in a distance away from the immovable layer 14. The immovable layer 14 is closer to the CPU than the moveable layer 16. Each contact 10 comprises a contact portion 100 connecting with the CPU by the solder balls 120, a rear portion 104 inserted into a PCB and a connecting portion (not labeled) connecting the contact portion 100 with the rear portion 104. The connecting portions have no isolating member such as an insulative housing arranged therebetween. Under a development of the computer technology, a supper fast data operation of the computer requires a supper fast data operation of the CPU, which causes a high density of the pins of the CPU. The contacts of the electrical connector connecting with the CPU result in a high density too. The connecting portions of the adjacent contacts are easy to be interfered with each other, more seriously, may cause shorting risk, because there is no isolating member such as insulative housing arranged therebetween.
Continue to refer to FIG. 2 of a cross-section view of an electrical connector as a second prior art, the electrical connector is connected with a CPU 22 by a plurality of solder balls 24 too, the same as the electrical connector of the first prior art. The electrical connector comprises an insulative housing 25 and a plurality of contacts 20. The insulative housing 25 defines a plurality of passageways 27 for receiving the contacts 20, therefore, each contact 20 is separated from the adjacent contact 20 by the insulative housing 25. Interference between the contacts 20 is avoided. Each contact 20 comprises a contact portion 200 connecting with the solder ball 24, a rear portion 204 inserted into a PCB and a curved connecting portion 202 connecting the contact portion 200 with the rear portion 204. The contact 20 is deflected in the passageway 27 when the CPU presses against the electrical connector, and an electrical connection between the contact portions 200 of the contacts 20 and the solder balls 24 are achieved. However, according to a high density of pins of the CPU, the passageways 27 receiving the contacts 20 are smaller. It provides limitation to a deflection of the contacts 20. Therefore, the electrical connection between the contact portions 200 of the contacts 20 and the solder balls 24 is influenced. The insulative housing 25 is made from rigid material, thus the contact 20 interferes with or even scraps the lateral walls of the insulative housing 25 when the contact 20 is pressed to deflect in the passageway 27. It may cause a lot of chips scrapped from the lateral walls of the insulative housing. The chips fall into the inner side of the electrical connector and influence a performance of the electrical connector. Furthermore, the insulative housing 25 has poor heat emitting ability. It will accumulate a lot of heat therein when the electrical connector works. It may cause deadly destroy to the electrical connector.
Hence, an improved electrical connector preventing interference between the adjacent contacts, having small space between the contacts but the contacts thereof having fine flexibility is desired.